The present invention relates to a non-contact type rotational position sensor, for example, suitable for detecting a rotational position (an opening degree) of a throttle valve of the internal combustion engine, a press-down position of an accelerator pedal and the like.
As a non-contact type rotational position sensor in place of a sensor using a potentiometer (contact type), for example, a sensor for detecting a displacement of a rotational body by use of magnetic sensitivity has been known.
In the non-contact type sensor of this kind, a permanent magnet is mounted on a body to be detected (a rotational body), a magnetic sensitive element is arranged in the vicinity of the rotational body, and the magnetic flux amount which changes according to the displacement of the rotational body is detected by the magnetic sensitive element to detect a rotational position.
In Japanese Patent Laid-Open No. 8-68606, an IC chip in which a magnetic sensitive element or an amplification circuit is integrated is used for a rotational position sensor. Further, in Japanese Patent Application Laid-Open No. 2000-74613, a magnetic sensitive element (a Hall element), an amplification circuit and the like are constituted in the form of 2-chip IC.
It is an object of the present invention to provide a non-contact type rotational position sensor which is allowed to achieve intensification of parts, miniaturization, simplification of assembly, and higher accuracy.
Further, the present invention is to improve the following point.
With respect to the demand of the higher intensification of a non-contact type throttle sensor portion and of enhancing the mounting density of parts, an arrangement of a circuit element (for example, such as a capacitor, a Zener diode, etc.) for the protection from electric disturbance noises and surge and a maintenance of a space thereof fail to respond to the above demand sufficiently under present conditions. The present invention is intended to realize such demand.
The first invention comprises a rotor for a sensor mounted on a rotating body to be detected, and a sensitive element sensitive to physical energy generated from the rotor and changed according to a rotational position of the rotor. A rotational position of the body to be detected is detected from an output of the sensitive element.
There is a housing made of synthetic resin for incorporating the rotor and the sensitive element. The housing is integrally provided with a connector provided with external connection terminals for connecting with external apparatuses.
Conductors for connecting the external connection elements to input/output terminals of the sensitive element are embedded into the housing by insert-molding. One ends of said conductors are exposed onto the surface of the inner wall of the housing at a fixed position where the input/output terminals of the sensitive element are present.
On the other hand, the inner wall of said housing is formed with a guide for guiding the input/output terminals of the sensitive element to the fixed position. The input/output terminals of the sensitive element are guided by the guide are joined to the one ends of the conductors at the fixed opposition.
The second invention comprises a housing made of synthetic resin having an axial hole for guiding one end of a rotational shaft to a bottom wall, and holding a magnetic plate (a lower stator) arranged around the axial hole;
a magnetic plate (an upper stator) mounted on the housing so as to oppose to the lower stator;
a cover for holding the upper stator and covering the housing;
a rotor having a magnet and mounted on one end of the rotational shaft and positioned between the upper stator and the lower stator; and
a magnetic sensitive element arranged between a magnetic projecting portion provided on upper stator and a magnetic projecting portion provided on lower stator.